In 1990, there is a split between MC1 and MC2. Look at the side of the engine, and see if there is 1 or 2 knock sensors. If it's 2, then you have an MC2, which has slightly higher compression, better cam, and K24 turbo. It's also possible it will have a 2 piece manifold.

I’m not sure if this would help but it’s fairly quick to jumper power to the cold start valve . If that was your issue you should have a start but then you’d still have to dig in to why it’s not working . The two wires I touch together every time I fire up my 80 do exactly that . Just takes about a one second squirt and no matter what I do will not start without it .

A 10V CIS can be impossible to start with a vacuum leak . I purchased an 85$ smoke tester on eBay and it has come in handy . Uses baby oil . You could put something together to use compressed air and soapy water . Finding a leak could help. Also of course checking fuses and relays . Have you looked at SJM autotechnik ? Their site has some good troubleshooting info and other useful stuff for MC engines .

JRH wrote:Thanks I'm going to try working on it this weekend. Any particular areas that I should look for vacuum leaks other than, well, all the rubber parts/tubes?

Those cloth lines , sometimes the cloth looks ok but its weak underneath. Any rubber hose that has a clamp if someone tightens the clamp too tight can tear the hose. There is a big vac line at the valve cover, some lines one going to the wastegate frequency valve, to the igloo, and I think maybe one going to the warmup regulator on the block, one goes to the ECU, charcoal canister.

Thanks. Found a leak in the PCV system - a 3 way rubber tube had a tear in it. I just plugged the crankcase vent system where it attaches to the intake manifold to disconnect it from the system. Also, weather is in the 40's today - up from 20's!

Car started right up! That was probably a vacuum leak, and also maybe the cold start valve isn't working. I'll try to unhook it and see if it will spray separately.

In the mean time, do you know where I can get that 3 way rubber connector that connects from the valvecover? It's the center portion of the photo:

I did also get an S&G gauge kit - it seemed like the control pressure and fuel pressure were within spec (compared to the bentley manual). Wonder what could cause a change in idle then - maybe more vaccum leak stuff?

Thanks. I put it back on. The variable idle I traced back to the CIS frequency valve (K-lambda). When it turned off the idle would rise. I unplugged it and the idle is steady ~800-900. Maybe something with the O2 sensor isn't right.

I already checked the fuel pressure is good, and it keeps pressure when shut off.

THe variable idle was solved by unplugging the CIS frequency valve. It would be ticking, turn off for a few sec, then start ticking again. Not sure why- maybe something with the ECU/lamba O2 sensor? Either way, for better or worse it is idling steady now. Probably not as fuel-efficient, but whatever.

still doesn't like to start when cold. I need to try jumping the cold start injector to see if that is the problem. The spray is adequate according to a reply here - so maybe it is something along the lines of it not being activated by the ECU? I think it is in line with the thermotime switch and I need to check that also.